This invention relates to electromagnetic interference (EMI) noise suppression filters, and more particularly, to the structural assembly of such filters.
One type of electrical power system used in aircraft includes a generator which is driven at a variable speed and is connected through rectifiers to a pair of DC link conductors. These conductors feed an inverter which synthesizes a 400 Hz sine wave by switching a plurality of transistor switches in accordance with an appropriate switching pattern. This type of power system is commonly called a variable speed constant frequency (VSCF) power system. An electromagnetic interference filter is required on the output of the inverter to eliminate high frequency noise caused by switching transients.
One type of EMI filter which has been used on VSCF power systems includes a plurality of generally cylindrical capacitors arranged in a generally rectangular array. Several ferrite inductive cores are mounted on one side of the array and feedthrough bus bars passed through these inductors. Capacitor bus bars are connected to terminals at one end of each capacitor and are typically brazed to the feedthrough conductors. Terminals extending from the other ends of the capacitors are shorted by a shorting plate. Although such filter assemblies perform their intended function, it is still desirable to provide an EMI filter assembly which is smaller in size, easier to assemble, and requires a smaller number of components.